30 Mercruiser carb setting

"I just bought a 2bbl re-man r

"I just bought a 2bbl re-man rochester off Ebay that will fit my mercarb manifold. I had continuous problems with trying to get the mercarb to work properly (rebuilt it twice) so I wanted to try the rochester. My service manual only has the mercarb settings. Can anyone please tell me what the idle mix and idle speed initial settings and in water (idle in gear) settings are? I now have 2 idle mix screws to deal with instead of one. Also, what should the idle rpm be at in and out of water? Thanks to all for help!"

"If this carb mounts to the ma

"If this carb mounts to the manifold correctly then this is what you have to do.

1. before stating engine turn both screws in carefully untill they stop turning, very lightly!!!

Then turn them both out 1 1/4 turns.

start engine and controll idle untill the engine is warm and the choke is wide open.

with the engine warm agjust idle screw (the one big screw on the side one controlls idle rpm so the engine is running at 600 to 700 rpms.

If engine is idling good at this rpm the very slowly turn one of the idle mixture srews in untill you notice a change in engine speed. when you find this turn the srew out untill you get the fastest motor speed.

Repeat for the second air mixture screw.

When you have reached the fastest motor speed adjusting both mixture screws set your main idle speed to ~700-750 rpms.

Put the boat in gear with NO throttle so the boat is moving only at idle speed.
Set idle speed screw so RPM'S are 650 -700 NO MORE. Spec is 650 to 750 in gear but the out drives like a bit slower such as 650 to 700."

"Thanks for the help. We took

"Thanks for the help. We took the boat out yesterday and tuned her. I actually had to lean out the mixture by about 3/4 turn each, but she idles at 650 and runs like a champ!"